Continuous central venous oxygen saturation (ScvO2) measurement using a fibre optic catheter in newborn infants.

AIMS To describe the range of central venous oxygen saturation (ScvO2) values in stable newborn infants breathing room air; to examine the correlation between ScvO2 and arterial oxygen saturation (SaO2); to describe fractional oxygen extraction; and the shunt index, an estimate of the venous admixture. METHODS A prospective clinical observational study was made of 10 preterm infants breathing room air after the acute phase of respiratory distress syndrome, and with an umbilical venous catheter in situ. A fibre optic catheter remained in the right atrium for continuous measurement of oxygen saturation. RESULTS ScvO2, SaO2, blood pressure and heart rate were registered every 15 minutes. Fractional oxygen extraction and shunt index were calculated. SaO2 and ScvO2 were 93.4 (SD 3.7)% and 73.56 (5.25)%, respectively. In seven patients ScvO2 values correlated significantly with SaO2. Fractional oxygen extraction was 0.21 (0.04) and was significantly correlated with ScvO2. The shunt index was 24% (12) and was significantly correlated with SaO2. CONCLUSIONS Stable preterm infants breathing room air had an ScvO2 ranging from 65% to 82% (5th and 95th percentile), which corresponded to SaO2 > or = 86%. ScvO2 values were significantly correlated with SaO2 in most patients.